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Create a new table `high_earners` containing only employees with salary above 80000. Then select from it.

Problem Statement

<p>Create a new table <code>high_earners</code> containing only <code>employees</code> with salary above 80000. Then select from it.</p>

Examples

Input: employees table: +----+---------+--------+ | id | name | salary | +----+---------+--------+ | 1 | Alice | 90000 | | 2 | Bob | 60000 | | 3 | Charlie | 120000 | | 4 | Dana | 75000 | +----+---------+--------+

Output: +----+---------+--------+ | id | name | salary | +----+---------+--------+ | 3 | Charlie | 120000 | | 1 | Alice | 90000 | +----+---------+--------+

Explanation: The query retrieves the requested records satisfying all problem requirements.

Complexity

Time Complexity: -

Space Complexity: -

Hints

šŸ’” Hint 1: Identify the filtering conditions needed to isolate the target rows from the table. šŸ’” Hint 2: Use appropriate operators: = for exact matches, LIKE for wildcard patterns, IN for sets, or BETWEEN for numeric/date ranges. šŸ’” Hint 3: Combine filters with AND/OR if multiple conditions exist: SELECT <cols> FROM <table> WHERE <condition>;

Editorial & Approach

Problem Overview & Intuition

To solve "CREATE TABLE AS SELECT (CTAS)", we query the relational database engine using declarative SQL. The goal is to create a new table `high_earners` containing only employees with salary above 80000. then select from it. By formulating an optimal execution plan with appropriate projection and filtering, the database engine executes the query with minimal overhead.

Step-by-Step Approach

  1. Analyze Schema: Identify the target tables, necessary foreign keys, and expected output columns.
  2. Construct Filtering & Logic: Apply WHERE filtering to isolate the requested data.
  3. Format & Order: Sort the resulting records according to specified order criteria.

Optimal Implementation (SQL)

CREATE TABLE high_earners AS SELECT * FROM employees WHERE salary > 80000; SELECT * FROM high_earners ORDER BY salary DESC;

Complexity Analysis

Time Complexity O(N log N) for sorting or partitioning rows.
Space Complexity O(N) for intermediate group hash tables or window buffers.

Key Considerations & Edge Cases

  • Empty Tables: The query executes safely returning zero rows without syntax error.
  • NULL Values: Columns containing NULL values are properly handled by standard ANSI SQL semantics.
  • Case Sensitivity: String comparisons and keywords adhere to PostgreSQL/standard SQL rules.

CREATE TABLE AS SELECT (CTAS)

Hard

Create a new table high_earners containing only employees with salary above 80000. Then select from it.

Example Scenarios
1Example 1
Input:
employees table
idnamesalary
1Alice90000
2Bob60000
3Charlie120000
4Dana75000
Output:
idnamesalary
3Charlie120000
1Alice90000
Explanation:

The query retrieves the requested records satisfying all problem requirements.

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